How to use this test
- Choose US or Spanish labels, then start the test. Keep the test area focused.
- Press and release each letter, number, modifier and arrow. A green key has produced a browser event.
- Hold two or three keys together. Compare the number held with the keys you are actually pressing.
- Pause before downloading the JSON report. Repeat on a different USB port or browser if a key is missing.
Read the observations
“Unique codes” counts distinct physical-position codes received by this page, not all switches on your keyboard. “Held now” counts keydowns without a matching keyup. “Auto-repeat” counts events marked repeat by the browser; holding a healthy key normally produces these events. If a combination fails, test each key alone, then try the combination again in another application. The test observes the input path, including your operating system and browser.
What this test cannot tell you
Fn, some media controls and system shortcuts may never reach a web page. Escape pauses this test. The drawing is a reference layout, not automatic hardware identification; the event line is the authority for keys outside it. KeyboardEvent.code describes a key position, while key describes the character produced by the active system layout. A browser test cannot certify USB polling rate, hardware latency or unlimited rollover.
Need a closer comparison? A key does not work: isolate the input path.
Questions about the test
Why does the label differ from my key?
The visual labels can be changed. Your operating system controls the character; the event line shows both the character and the physical-position code.
Does a green key prove the keyboard is fault-free?
It proves that an event reached this page during this session. Intermittent faults and problems specific to another application need separate checks.
Technical references
Method version 2.0 · Page updated 2026-10-20